 #define _CRT_SECURE_NO_WARNINGS 1

class Solution {
public:
    int takeAttendance(vector<int>& records) {
        int left = 0, right = records.size() - 1;

        while (left < right)
        {
            int mid = left + (right - left) / 2;
            if (mid == records[mid]) left = mid + 1;
            else right = mid;
        }

        return left == records[left] ? left + 1 : left;
    }
};